1. Field of the Invention
The present invention relates to microwave routing or switching devices, such as microwave waveguides, and devices and systems including same. Particularly, the present invention relates to selectively controlling the transmission of microwave energy via at least one electrical arc.
2. Background of Related Art
Conventional microwave switch devices are known in the art for switching microwave signals. Typically, such conventional microwave switches may be mechanically actuated (e.g., via rotary or linear movement) and may be configured for opening or closing apertures (within a waveguide, for instance) for allowing or preventing microwave energy transmission.
For example, some mechanical microwave switches, described in U.S. Pat. No. 6,037,849 to Ciezarek, include an actuator plate, which is mechanically coupled to reeds of a connection assembly, that may be employed for placing the connection assembly into the selected position. Thus, during operation of the switch, a magnetic force of a permanent magnet may be substantially the only holding force that holds the actuator plate (coupled to various reeds) in place in at least one direction. In another example, a prior art microwave switch of a rotary type is described in U.S. Pat. No. 4,370,631 to Gerber et al., and comprises a rotor, a rotor housing, two biasing means, a housing for the biasing means and an electronic circuit to control the biasing means. The rotor and the housing are of conventional design. The biasing means comprise two rotary solenoids, which are mechanically linked to a Maltese transmission mechanism.
Microwave switches may be employed in a variety of applications, including microwave heating/processing, space applications, or other applications. Of course, performance considerations, such as the amount of time for actuating the switch may be of importance. It may be difficult to manufacture parts for a mechanical microwave switch with sufficiently high precision to permit suitable control of microwave energy. Furthermore, mechanical systems may be prone to relatively slow actuation times (i.e., switching times) and also may be prone to mechanical failure. It may be, therefore, desirable to provide a microwave switch with an actuation mechanism that is efficient, reliable, and which exhibits a relatively low actuation time.
Accordingly, some conventional microwave switching devices have been conceived that are non-mechanical microwave switching devices. For example, U.S. Pat. No. 2,493,706 to Washburne et al. discloses an electronic switch for electronically switching and modulating microwaves. More particularly, the conventional device includes an evacuated waveguide wherein an electron beam may be generated for reflecting at least a portion of microwave energy.
In another example, U.S. Pat. No. 3,281,719 to Goldberg discloses a microwave switching apparatus utilizing a spark gap inserted parallel to an electric field wherein a trigger pulse applied to the spark gap ionizes the gas in the vicinity of the gap and the microwave energy being propagated through the waveguide system causes breakdown to occur between the electrodes of the spark gap, thus creating a microwave arc.
In yet a further example, U.S. Pat. No. 4,255,731 to Birx discloses a microwave switching apparatus for producing a beam of electrons, which traverses a central portion of the narrow dimension of a rectangular cavity in a direction parallel to the electrical field of microwave energy traveling therein. The electron beam switch is intended to be used for the purpose of suddenly releasing very large amounts of stored energy accumulated in a waveguide during its so-called “open” state.
These electronic microwave switches described above may be configured for inhibiting transmission of microwave energy or releasing stored microwave energy in a single waveguide. However, there is a need for routing microwave energy to multiple output waveguides while enabling selective transmission of the microwave energy into those output waveguides. In addition, it may be desirable to provide a microwave routing element with an electronic actuation mechanism that is efficient, reliable, and which exhibits a relatively low actuation time relative to mechanical microwave switches.